Running a dual boot with XP and Ubuntu 7.10 on my Thinkpad, I notice that
Ubuntu's power management does not seem to perform nearly as well as XP's.
I get more than 50% more battery life running XP than with Ubuntu.

Google doesn't seem to be telling me much that's useful. The power
management options provided under "Preferences" seem pretty basic, and
don't do much to improve things.